The present invention relates to temperature monitoring of blood bags and other packaged frozen materials which must be transported and/or stored, all the while maintaining their respective contents below a predetermined upper temperature limit. The present invention provides an inexpensive, discardable temperature monitoring unit which may be dedicated to an individual package, but which reliably provides an indication of excessive temperature history if it occurs.
Temperature monitoring of blood bags and the like is described in detail in my U.S. Pat. Nos. 3,483,752 and 3,440,997.
It is an important object of the present invention to provide inexpensive temperature monitoring of refrigerated materials.
It is a further object of the invention to provide reliable temperature monitoring consistent with the preceding object.
It is a further object of the invention to provide non-invasive temperature monitoring consistent with one or both of the preceding objects.
It is a further object of the invention to provide a temperature monitoring device which can be dedicated to a particular package to be monitored consistent with one or more of the preceding objects.
It is a further object of the invention that the device be settable in a manner that is apparent to any operator consistent with one or more of the preceding objects.
It is a further object of the invention that the device provide an indication of setting, distinguishable from indication of temperature excess consistent with one or more of the preceding objects.
It is a further object of the invention that the indications be visual and quite obvious consistent with one or more of the preceding objects.